1. Field of the Invention
The present invention relates to a back light assembly, and more particularly, to a back light assembly rendering elements thereof to be orderly stacked and assembled in a receiving space of the mold frame, thereby enhancing the assembly capability and simultaneously finding a failed element easily during the assembly process. Further, the invention relates to an LCD (Liquid Crystal Display) having a back light assembly in which elements are orderly stacked and assembled. Still further, the invention relates to an assembly method of these elements.
2. Description of the Related Art
In these days, as semiconductor fabrication technologies are rapidly advanced, semiconductor devices having an ultra fine line width, for example, switching devices such as the thin film transistors are being developed using such semiconductor fabrication technologies.
Thin film transistors are used in the flat panel display devices such as liquid crystal displays, plasma displays, etc., as well as the memory device such as DRAM (Dynamic Random Access Memory) and CPU (Central Processing Unit).
Especially, as the semiconductor thin film transistors are applied to the display devices, the display devices become lighter in weight, smaller in volume and slimmer in thickness compared with the conventional CRT (Cathode Ray tube) displays.
In order to achieve these less voluminous, light, smaller and slimmer displays, it is necessary to divide a predetermined sized screen into a plurality of fine pixels matched with its resolution and to drive the divided fine pixels selectively. Especially, in LCDs, there are required various important technologies, such as liquid crystal technology using an electric potential forming unit that allows power to be selectively supplied to the fine pixels and an electric field generated by the electric potential forming unit, liquid crystal driving technology for controlling the light transmittance by the liquid crystals, an optical technology for increasing luminance of light passing through the liquid crystal and providing uniform luminance and assembly technology for assembling various elements related to the aforementioned technologies.
Recently, in addition to optimizing these technologies, there are many endeavors for decreasing the width and thickness of the LCD panels by improving the assembly technology such as reducing the number of assembly elements and the number of assembly processes, etc.
In LCD monitors widely used in desktop computers and notebook computers, an LCD panel assembly and a backlight assembly are respectively assembled by separate assembly processes and they are then assembled to each other. Hereinbelow, their assembly processes are described.
First, a mold frame is furnished to simultaneously fix the backlight assembly and the LCD panel assembly. A series of optical sheets, a light guiding plate, a lamp assembly, a reflector plate and a bottom chassis are stacked in order in the mold frame.
Then, the LCD panel assembly is mounted on the mold frame. Thereafter, the backlight assembly, the mold frame and the LCD panel assembly are firmly fixed by the chassis.
However, in the conventional assembly method, where the optical sheets are assembled before the lamp assembly, the contaminated optical sheet may be assembled undetected or the lamp assembly may not operate.
Also, the reverse type may not allow the elements inspected during the LCD inspection, and also increases the assembly time and the LCD size.
It is therefore an object of the present invention to assemble an LCD assembly more efficiently in an order where the elements of the LCD assembly are placed.
It is another object of the present invention to achieve a slim display module by simplifying the structure of the display module.
It is still another object of the present invention to decrease the time spent in the assembly.
To achieve the above objects and advantages, there is provided a backlight assembly comprising: a mold frame having a receiving space furnished by an inner lower surface and plural side walls normal to the inner lower surface; a reflector plate mounted on the lower surface of the mold frame; a light guiding plate disposed on the reflector plate; a lamp assembly accommodated between one side portion of the light guiding plate and the side walls of the mold frame facing with the one side portion of the light guiding plate; a series of diffusion sheets disposed on the light guiding plate; and a pair of fixing frames facing with each other, covering an edge of the light guiding plate corresponding to an accommodated place where the lamp assembly is accommodated and the side walls of the mold frame, pressing and fixing the light guiding plate and being detachably coupled to the mold frame.
Preferably, the lamp assembly comprises: a reflector mold that is first bent to define an inner space and an outer space and having a constant thickness; a lamp accommodated in the inner space of the bent reflector mold; a lamp holder established at both ends of the reflector mold, for fixing both end portions of the lamp; a reflector sheet attached on a surface of the inner space of the reflector mold; and a lamp wire accommodating groove formed along a length direction of the reflector mold at a face of the outer space of the reflector mold such that a lamp wire for supplying a power to one electrode of the lamp is accommodated.
Preferably, the fixing frame comprises: a body having a constant thickness and which is first bent to define an inner space and an outer space; a pressing protrusion formed along a length direction of the body at a lower face of the inner space of the body and having a selected height; and a guide protrusion formed at both ends of an upper face of the outer space of the body, for guiding an LCD panel when assembling the LCD panel.
Preferably, the body of the fixing frame comprises a plurality of through holes spaced apart by a constant distance and the mold frame comprises a plurality of coupling protrusion formed at the side wall of the mold frame, wherein the fixing frame is coupled to the mold frame by hook-coupling the coupling protrusion of the mold frame to the through holes of the fixing frame.
Preferably, the body comprises a reflector sheet attached at a portion facing with the lamp in the lower face of the inner space of the body.
Preferably, the lower face of the outer space of the body is in contact with the lower surface of the mold frame and the mold frame comprises a mounting groove having a selected depth and formed at the contact portion of the lower surface of the mold frame.
Preferably, the lower face of the outer space of the reflector mold faces with the fixing frame and a reflector sheet is attached to the reflector plate facing with the lower face of the inner space of the reflector mold.
Preferably, the series of diffusion sheets comprises a diffusion sheet that is directly in contact with the light guiding plate and has the largest area than the remaining diffusion sheet.
According to another aspect of the present invention, there is provided a liquid crystal display comprising: a backlight assembly including: a mold frame having a receiving space furnished by plural side walls; a reflector plate mounted on a lower face of the mold frame; a light guiding plate disposed on the reflecting plate; a lamp assembly accommodated between one sided end portion of the light guiding plate and the side walls of the mold frame facing with the one sided end portion of the light guiding plate; a series of diffusion sheets disposed on the light guiding plate; and a pair of fixing frames facing with each other, covering an edge of the light guiding plate corresponding to an accommodated place where the lamp assembly is accommodated and the side walls of the mold frame, pressing and fixing the light guiding plate and being detachably coupled to the mold frame; an LCD panel assembly whose edges facing with each other are established to be overlapped with end portions of the pair of fixing frames on the end portions of the pair of fixing frames; and a chassis integrally coupling the LCD panel assembly and the backlight assembly.
According to still another object of the present invention, there is provided a method for assembling a backlight assembly, comprising steps of: mounting a reflector plate on a lower surface of a mold frame having a receiving space therein; mounting a light guiding plate on the reflector plate; mounting at least one sheet of diffusion plate on the light guiding plate; inserting a stack type lamp assembly into a space between one end portion of the light guiding plate and an inner surface of the mold frame; and coupling a fixing frame and the mold frame such that the fixing frame covers an outer surface of the mold frame and presses an upper surface of the light guiding plate.